Pregnancy outcomes following systemic prenatal acyclovir exposure--June 1, 1984-June 30, 1993

Herpes infections are common among women of reproductive age (i.e., aged 15-44 years). Acyclovir (Zovirax), an antiviral drug effective in the treatment of herpes simplex infection, was approved by the Food and Drug Administration (FDA) in 1984. Since its approval, the effects of acyclovir on human pregnancies have not been determined. However, inadvertent pregnancy exposures to acyclovir were expected to occur among women in whom treatment had been indicated for preexisting herpes simplex infections. Some physicians have reported intentional use of acyclovir during pregnancy for treatment of life-threatening herpes simplex infection. To assess the outcomes of pregnancies exposed to acyclovir, the Acyclovir in Pregnancy Registry was established on June 1, 1984, by the manufacturer, in collaboration with CDC. This report summarizes data on pregnancies reported to the registry through June 30, 1993.